Foot-and-Mouth Disease Virus-Associated Abortion and Vertical Transmission following Acute Infection in Cattle under Natural Conditions

Abstract

Foot-and-mouth disease (FMD) is a highly contagious and economically important viral disease of cloven-hoofed animals, including domestic and wild host species. During recent FMD outbreaks in India, spontaneous abortions were reported amongst FMD-affected and asymptomatic cows. The current study was an opportunistic investigation of these naturally occurring bovine abortions to assess causality of abortion and vertical transmission of FMDV from infected cows to fetuses. For this purpose, fetal tissue samples of eight abortuses (heart, liver, kidney, spleen, palatine tonsil, umbilical cord, soft palate, tongue, lungs, and submandibular lymph node) were collected and screened by various detection methods, including viral genome detection, virus isolation, and immunomicroscopy. Amongst these cases, gross pathological changes were observed in 3 abortuses. Gross pathological findings included blood-tinged peritoneal and pleural effusions and myocarditis. Hearts of infected calves had mild to moderate degeneration and necrosis of the myocardium with moderate infiltration by mixed inflammatory cells. Localization of FMDV antigen was demonstrated in lungs and soft palate by immunomicroscopy. FMDV serotype O viral genome was recovered from 7 of 8 cases. Infectious FMDV serotype O was rescued by chemical transfection of the total RNA extracted from three soft palate samples and was sequenced to confirm 100% identity of the VP1 (capsid) coding region with isolates collected from infected cattle during the acute phase of infection. Based upon these findings, it may be concluded that FMDV-associated abortion occurred among the infected pregnant cows included within this study and FMDV was subsequently transmitted vertically to fetuses. This is the first documentation of FMDV-associated abortions in cattle.

Quantitative characteristics of the foot‐and‐mouth disease carrier state under natural conditions in India

“…The outbreaks described herein were previously shown to be associated with FMDV serotype O by multiplex PCR (Ranjan, Biswal, Subramaniam et al., ). Serotype O is the most common serotype of FMDV associated with outbreaks in India, accounting for 80% of the outbreaks nationally (Biswal et al., ) and nearly 50% of outbreaks in the neighbouring state of Uttar Pradesh (Verma, Pal, Singh, Udit, & Yadav, ).…”

“…Immediately subsequent to the outbreaks, FMDV lineage O/ME‐SA/Ind‐2001d was identified by sequence analysis from multiple clinical samples from both farms. Further genomic, antigenic and clinical characterizations of the FMDV isolates from the farms included in this study have been reported in separate publications (Ranjan, Biswal, Subramaniam et al., ; Subramaniam et al., ).…”

Knowledge and perception of pastoral community members about brucellosis as a cause of abortion in animals and its zoonotic importance in Amibara district, Afar Region, Ethiopia

“…The pastoral community members’ concern about foot and mouth disease as a cause of abortion in their cattle is similar to the findings of a study by Kothalawala et al [ 27 ] in Sri Lanka where farmers identified this disease as a cause of abortion in their cattle, but they had no adequate information regarding brucellosis as a cause of abortion in animals. Evidence also shows that foot and mouth disease causes abortion in cattle [ 28 , 29 ].…”

Foot‐and‐mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India

“…Additional cases were recorded for 39 days until the last new case of FMD on the farm was reported on 31 January 2014. Genomic analyses of viral isolates collected during the outbreak indicated that the causative strain categorized within O/ME‐SA/Ind‐2001d lineage (Ranjan et al., ). The vaccine strain used at this time in India belonged to O/IND/R2/75 lineage (Subramaniam et al., ), and recent studies have suggested that this vaccine strain provides adequate protection against infection caused by strains belonging to O/ME‐SA/Ind‐2001d lineage (Subramaniam et al., ).…”